This invention is concerned with a bottom plate mechanism for a mould of a glassware container manufacturing machine comprising an adaptor plate which provides a support for one or more mould bottom plates and contains passages which connect an inlet of the adaptor plate to the or each bottom plate supported thereby so that, when vacuum is applied to the inlet, air is sucked from the or each bottom plate, connecting means on which the adaptor plate is mounted which connects the inlet to a vacuum source, a filter which serves to prevent particles sucked from the or each bottom plate from reaching the vacuum source, and height adjustment means operable to vary the height at which the adaptor plate is supported, the connecting means being arranged to maintain the connection between the inlet and the vacuum source as the height of the adaptor plate is varied.
A conventional glassware container manufacturing machine of the so-called "individual section" type has parison forming means which operates to form a parison out of molten glass. The formed parisons are then transferred to moulds in which they are blown to the shape of the container required. These moulds comprise a bottom plate which remains stationary during the operation of the machine and two side portions which are movable toward and away from one another to open and close the mould. While the parison is blown in the mould, air is sucked from the mould through the bottom plate so that the air does not prevent the parison from reaching the shape required. To this end, the bottom plate or, where two or more moulds are operated together, the bottom plates are mounted on an adaptor plate which supports them and contains passages which connect an inlet at the bottom of the adaptor plate to the or each bottom plate so that, when vacuum is applied to the inlet, air is sucked from the bottom plate or plates.
In conventional machines, the adaptor plate has a downward projection in which the inlet is formed and is clamped, by means of a clamping ring which acts on the downward projection, to a bracket of the machine. The bracket is mounted for heightwise sliding movement on a frame of the machine and height adjustment means is operable to vary the height at which the bracket is supported on the frame and therefore the height at which the adaptor plate is supported. The bracket forms connecting means operable to connect the inlet of the adaptor plate to a vacuum source. To this end, the bracket contains two ducts, one of which communicates with the inlet of the adaptor plate and the other of which receives in a telescopic manner a cylindrical end portion of a fixed duct which passes to the vacuum source. The two ducts communicate with one another through a valve mounted in a cartridge which is bolted to the bracket and is operable to either connect the two ducts together so that vacuum is applied to the adaptor plate or to break the communication between the ducts. The cartridge also contains a filter extending across one of the ducts which serves to prevent particles of molten glass or other debris sucked from the or each bottom plate from reaching the vacuum source where it might do damage.
In the conventional bottom plate mechanism mentioned above, it is sometimes necessary to change the filter as it becomes clogged with debris. To do this, the cartridge is unbolted from the bracket and either replaced by another cartridge or the filter is removed from the cartridge, and replaced by another filter, and the cartridge is rebolted to the bracket. In both cases, the operation of the machine has to be suspended for a considerable period during which the replacement of the cartridge takes place so that considerable delays in the operation of the machine are experienced. Furthermore, where the entire cartridge is replaced, a supply of cartridges needs to be maintained which is expensive. When the adaptor plate requires changing, it is necessary to loosen the aforementioned clamping ring which also creates delays in the operation of the machine.
It is an object of the present invention to provide a bottom plate mechanism for a mould of a glassware container manufacturing machine in which the filter can be changed more rapidly than in the aforementioned conventional machine with a consequent saving in production losses.